This invention relates to the preparation of optical grade tantalum oxide which is of high purity.
High purity tantalum and/or niobium compounds can be produced by ion exchange or solvent extraction processes. Said ion exchange or solvent extraction processes require large outlays of equipment and raw materials. Such methods are described in the following U.S. Pat. No. 3,107,976, 2,895,793, 2,880,060, 2,819,945, 4,182,744, 4,069,268, 4,065,405, 3,972,710.